In a multi-voltage system, integration of more than one type of integrated circuit (IC) in a functional system is common. Consequently, there is a necessity for a level shifter circuit that is configured to shift the voltage level at the output of one IC to the voltage level at the input of another IC. For example, the output of an IC that operates at a higher voltage level may be provided to another IC that operates at a lower voltage level. In this instance, the voltage needs to be ramped down to a lower level. Similarly, when the output of an IC that operates at a lower voltage level is input to an IC that has a higher operating voltage, the voltage needs to be ramped up.
A limitation of a conventional level shifter with embedded logic is that the level shifter and corresponding logic are typically designed between the multi-voltage ICs in a cascading relationship such that there is unnecessary delay added to the ICs. For example, conventionally a first supply voltage domain is input into a level shifter from a first IC, the level shifter outputs a second supply voltage domain different from the first supply voltage domain, the second supply voltage domain may be input into the logic (e.g., true logic) as a signal, and subsequently the logic acquires a function based on the input second supply voltage domain, which is input into a second IC. Thus, there is unnecessary delay added to the IC because initially the level shifter is configured to ramp up or down the first supply voltage domain to the second supply voltage domain (e.g., introducing a first delay), and subsequently, the logic is configured to acquire a function using the second supply voltage domain provided by the level shifter (e.g., introducing a second delay).
In view of the foregoing, there is a need for a level shifter circuit that supports a voltage level shifting function as well as a built-in-logic function without leading to extra delay in the ICs in comparison to a cascaded system. Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.